The number of dedicated traffic police officers has fallen by nearly a third in 10 years, an investigation has revealed.
Experts have questioned how new laws, such as the ban on using mobiles while driving, can be enforced with 30% fewer officers dedicated to policing roads.
The Press Association submitted a Freedom of Information (FOI) request to all 45 territorial forces asking how many dedicated traffic officers they have compared with five and 10 years ago.
The results reveal cuts have accelerated in the past five years with numbers falling 24% since 2012, while overall the number is down 30% since 2007.
In 2007 there were 3,766 traffic officers in the forces which responded. In 2012 that figure stood at 3,472. By 2017 it had dropped to 2,643.
A number of forces increased the number of traffic officers between 2007 and 2012, but as budget cuts bit these numbers were reduced between 2012 and 2017.
The AA said the decline could see more drivers getting away with crimes.
A spokesman said: "We need more cops in cars, not fewer.
"The UK has among the safest roads in Europe, although the number of people killed and seriously injured on our roads has started to rise after many years of steady decline. Maybe there is a link?"
He added: "Even senior officers have publicly expressed concern at the falling number of their colleagues."
Responding to the figures, the Home Office said effective road policing is not just dependent on dedicated traffic officers, while the National Police Chiefs' Council (NPCC) pointed out that all officers were able to help traffic specialists.
In total, 30 forces released figures.
Of the rest, 11 did not hold data for the full 10 years and three had merged traffic into tri-force operations.
Merseyside was the only force which failed to send the figures to PA.
Gwent saw the biggest drop, from 94 traffic officers in 2007 to none now. Northamptonshire dropped 83% with nine dedicated officers currently compared with 52 in 2007.
Gwent said it had amalgamated traffic officers into "multi-skilled roles" while Northamptonshire said it had "regionalised" its road traffic officers.
Greater Manchester Police traffic officer numbers dropped 69% in the past 10 years (241 to 75), Nottinghamshire's fell 56% (138 to 61), while the West Midlands cut numbers by 52% from 384 in 2007 (the most outside London) to 186 officers today.
Hertfordshire (up 44%), Northumbria (up 32%), West Mercia (up 26%), Surrey (up 14%) and Sussex (up 11%) were the only forces to increase numbers.
Labour's shadow minister for policing and crime Louise Haigh, a former special constable, said: "These savage cuts will deeply alarm the public as reckless drivers will feel able to offend with impunity."
She added: "There have been a number of new driving offences in the last few years, not least relating to phones and the new offence of causing serious injury by dangerous driving.
"The police don't stand a cat in hell's chance of pursuing and convicting people under these offences with ever-constrained resources."
Jason Wakeford, from road safety charity Brake, commented: "On average, five people die every single day on our roads. This is unacceptable.
"The Government and police forces have to start treating road policing as a national priority and reverse the savage cuts to officer numbers."
However, West Mercia Chief Constable Anthony Bangham, who speaks on roads policing for the NPCC, said: "Individual police forces decide how best to allocate resources and keep their communities safe.
"Some may choose to reduce the numbers of specialist traffic officers, but this does not mean that their roads are not adequately policed.
"They can deploy a range of resources, including ANPR (Automatic Number Plate Recognition) technology, targeted patrols using unmarked vans, high vantage points and helmet cams to catch offenders.
"All police officers are available to help those who are traffic policing specialists."
The Home Office said deployment of resources was a matter for chief constables and crime commissioners, who "understand their operational needs better than anyone".
A spokesman said: "The Government has protected overall police spending in real terms since the Spending Review 2015 and we will always ensure forces have the resources they need to do their vitally important work.
"Effective roads policing is not necessarily dependent on dedicated road traffic officers: the use of technology, other police personnel and local communities also have a role to play."
But Jayne Willetts, who speaks on roads policing for the Police Federation of England of Wales, which represents rank and file officers, said cuts meant specialist roads policing officers now face added demands.
"They are having to attend calls for help from the public in addition to patrolling the road network to target travelling criminality."
She added: "The introduction and use of new technology is welcome but the visibility of the police cannot be overstated as a deterrent and a reassurance to the public.
"Unfortunately the thin blue line is becoming too thin."